Aquarium gravel comes in all shapes and sizes. While gravel is the most popular aquarium substrate, all of the options may get confusing. Then when you throw in other substrates like sand and soil, who knows what to choose? Just keep in mind the following when choosing your aquarium substrate. There are only a couple key functions of any fish tank substrate. They anchor your plants and roots. They support your fish tank rocks and wood. Other than that, they are mostly just for plain old decoration. There are however, some basic things you should know about aquarium gravel to save yourself some trouble later.
Natural Gravel
Pea gravel is the most popular of available aquarium gravel substrates. Choose a size that is at least 4mm in order to get optimal performance. Gravel of this size will allow good water flow through it keeping the area water from becoming stagnant. You also need to pay attention to whether the aquarium gravel you choose is inert or not. If it is, it will say it on the package or in the description. Inert aquarium gravel should have no effect on the chemical balance of your aquarium.
Need pH?
Other choices like crushed coral that are not inert, can raise the pH levels. For most freshwater tanks, this is not a desired effect. Saltwater tanks, African Cichlid tanks, and other tanks with only fish requiring high pH levels are the only cases when you should consider something other than inert gravel. Fish tanks of this type should ideally have a pH level of 8.0 or higher. Crushed coral, marble, limestone, or other pH lifting gravels are suggested.
Sand
Sand is not usually suggested for most aquariums. However, if you insist on sand, silver sand is the most common aquarium sand and you can find it at your aquarium retailer. Silver sand is an inert substrate with of course, very fine granules. These fine granules are the biggest problem with using sand as a substrate. Sand compacts and will not allow adequate water flow and oxygenation of the water in the bed. This eventually leads to unwanted bacteria growth and root rot of your plants. If you are willing to stir your sand up every couple of days you can make sure this does not lead to problems. This is just additional maintenance that is probably not worth the trouble.
Soil
You can probably guess that soil can lead to a muddy mess and therefore is not suggested as a substrate. Although soil is probably not ideal, it can be good for plant growth because if its higher iron content. When using soil, it is usually not necessary add additional nutrients to soil. This is however, necessary for most other substrates if your tank has plants. If you do choose to use soil as a substrate, make sure you use aqua soil that is specifically designed for aquariums.
2 responses so far ↓
1 Mary // Dec 14, 2007 at 6:57 am
I believe natural gravel can also act as a breeding ground for the good bacteria your fish and fish tank need.
2 Hevach // Apr 25, 2008 at 8:13 pm
If you use sand, I suggest getting a loach species that burrows like kuhli loaches. They’ll help keep it stirred up for you. I don’t think you can use an undergravel filter with sand, but kuhlis have been known to take up residence inside them and cause problems.
Many eels burrow, also, but tankmates have to be chosen carefully, as they may kill smaller tankmates.
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